Math – Applications for Living VI

Statistics in the news!!

The report (from the BBC) cites a study which says “55% of Syrians think President Assad should stay”.  The source is http://www.bbc.co.uk/news/magazine-17155349

This is a case where the journalist actually did a good job with the statistics.  The quote above comes from an online survey done with about 1000 respondents in the middle east and north Africa.  The article describes several statistical problems with the conclusion.  Among them:

  • Syrians live (generally) in Syria … the report did not state how many were actual Syrians or lived there.  One reference in the report allows an estimate of about 100.
  • One thousand is a modest number for a survey — this one covers an entire region.
  • One hundred is statistically insufficient to measure the opinions of a country.
  • Few Syrians have internet access; since it was an internet survey, the Syrians who did respond are not likely to be representative of all Syrians.

Curiously, our Math — Applications for Living class (Math119) yesterday covered a ‘rule of thumb’ for the margin of error for polls like this.  For most polls, the quick little formula 1/√n (reciprocal of the square root of the sample size) is surprisingly accurate.   For the 100 Syrians actually included in the results, the margin of error is 10% .. the true population parameter would be between 45% and 65% (most likely!).

The sad part of this story is that the original story on this survey did not provide this more complete context for the results.  Take a look at the BBC report for more information on that.  One can only hope that the bad use of statistics does not contribute to an already bad situation.

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